Is there a way to start notepad++ with tail -f from command line for a *.txt or *.log file ?
notepadd++.exe C:\temp\logfile.log /tail -f or something…
According this npp manual, no.
A possible approach to this issue is use send keys tools, it can open npp with the file and then send the shortcut keys to set tel tail -f module.
By the way this question give me a idea to request a cmd line key like this /macro=myMacro and will be possible extendo the npp processing including solving your problem.